Well, from looking at the plate "forks" of the 6dj8/ecc88
I can't determine if mechanical resonation in one plate
will always couple to its twin. Even if they did, how to
begin to guess if that would be in or out of phase? Nor
how closely those mechanical resonances are matched.
But there exists a high impedance voltage divider
internal to every triode (or pentode with a triode
strapped screen) that provides linearizing negative
local feedback, intrinsic feedback...
It occours to me that several triodes with mechanically
isolated microphonics acting in parallel, the feedback
path from the "other" plates might actively attempt to
correct one exception that might have picked up a
microphonic, and more so than a mere noise average.
What if I took say four 6dj8's and wire the "left" triodes
in parallel, and then the "right" triodes in Mu Follower,
are parallel triodes less microphonic than a single triode
in any significant way?
I can't determine if mechanical resonation in one plate
will always couple to its twin. Even if they did, how to
begin to guess if that would be in or out of phase? Nor
how closely those mechanical resonances are matched.
But there exists a high impedance voltage divider
internal to every triode (or pentode with a triode
strapped screen) that provides linearizing negative
local feedback, intrinsic feedback...
It occours to me that several triodes with mechanically
isolated microphonics acting in parallel, the feedback
path from the "other" plates might actively attempt to
correct one exception that might have picked up a
microphonic, and more so than a mere noise average.
What if I took say four 6dj8's and wire the "left" triodes
in parallel, and then the "right" triodes in Mu Follower,
are parallel triodes less microphonic than a single triode
in any significant way?
Hi
well I am a SE lovers. Minimalist, symplistics,less is better and so on.
I actually have a 6922 common cathode direct coupled to cathode follower . It sounds quite good but I'm not completely satisfied.
I have thinked a simple anode output maybe can sound more natural,
but I have to parallel two ( ala CJ Art) to obtain 1200-1300 ohm.
This remain the last option.
But before I want try a single triode philosophy.
I can say the sowtek 6922 has zero microphonicity, usually I hit (?
touch ) the glass with a wood pencil and I can't hear zero from the speaker
This is my poor-man requirement.
We will see the ECC182 I hope.
thanks for comment
Cheers,
Paolo
well I am a SE lovers. Minimalist, symplistics,less is better and so on.
I actually have a 6922 common cathode direct coupled to cathode follower . It sounds quite good but I'm not completely satisfied.
I have thinked a simple anode output maybe can sound more natural,
but I have to parallel two ( ala CJ Art) to obtain 1200-1300 ohm.
This remain the last option.
But before I want try a single triode philosophy.
I can say the sowtek 6922 has zero microphonicity, usually I hit (?
touch ) the glass with a wood pencil and I can't hear zero from the speaker
This is my poor-man requirement.
We will see the ECC182 I hope.
thanks for comment
Cheers,
Paolo
I got 6dj8's, lots of them. And I intend to put them to
good use. Not buy more or better tubes when I already
have so many. But they amost certainly be microphonic,
and figuring how to work around that is important to me.
Smoking Amp had suggested that all triodes consist
of multiple triode paths of different characterisics.
The more consistant triode average looks like a 300b
with nice parallel curves. Average of poorly matched
triodes (or internal paths) leans to the right as those
different paths do not enter cutoff in unison.
But even those triodes that do lean, or multiple triodes
of poor match acting in parallel, will have a consistant
Mu voltage gain when held at constant current. That
would be the way I would attempt to run them, rather
than cross the leaning curves with a resistive loadline.
good use. Not buy more or better tubes when I already
have so many. But they amost certainly be microphonic,
and figuring how to work around that is important to me.
Smoking Amp had suggested that all triodes consist
of multiple triode paths of different characterisics.
The more consistant triode average looks like a 300b
with nice parallel curves. Average of poorly matched
triodes (or internal paths) leans to the right as those
different paths do not enter cutoff in unison.
But even those triodes that do lean, or multiple triodes
of poor match acting in parallel, will have a consistant
Mu voltage gain when held at constant current. That
would be the way I would attempt to run them, rather
than cross the leaning curves with a resistive loadline.
Hi guys,
I'm testing first 6N6P-I.
see thread :" help for E182CC linestage/driver" post 21
Very little microphony at one channel. Not satisfied
I have other 9 to try, maybe i will be lucky?
It is a pity, all the others parameters ( excerpt life time) looks fantastic to my inexpert eyes.............
I was to much good accustomed with my old sowtek 6922, maybe more unique than rare!
Cheers,
Paolo
I'm testing first 6N6P-I.
see thread :" help for E182CC linestage/driver" post 21
Very little microphony at one channel. Not satisfied
I have other 9 to try, maybe i will be lucky?
It is a pity, all the others parameters ( excerpt life time) looks fantastic to my inexpert eyes.............
I was to much good accustomed with my old sowtek 6922, maybe more unique than rare!
Cheers,
Paolo
Hi,
6N1P is basically an ECC85 and 6N2P is an ECC83 with a different heater wiring. Don't know about 6N6P though. I would recommend these tubes as they are cheap as dirt and most are made to military specs.
Here are datasheets for most common Russian tubes: http://www.rutubes.com/index.php?show_aux_page=3
6N1P is basically an ECC85 and 6N2P is an ECC83 with a different heater wiring. Don't know about 6N6P though. I would recommend these tubes as they are cheap as dirt and most are made to military specs.
Here are datasheets for most common Russian tubes: http://www.rutubes.com/index.php?show_aux_page=3
inertial said:Hi,
More accurately, I'm searching info about a near zero microphonic medium mu double triode. Low Rp is requested.
candidates are
E182 CC , ECC99, 5687, 6H30 or others
I have some E288CC philips SQ but they ring like bells
I can considerate also single triode.
I know EC8020 is the best but they are ultra expansive !
I appreciate any kind of suggestion
Thanks for help,
Paolo
So far, I've used Sovtek 6SL7s and 6SN7s -- not microphonic at all. The other dual triode I've used is the 6BQ7A. With these, I've found that Sylvanias with the heaters in series were nastily microphonic. The parallel heater Sylvanias and the Motorolas (also parallel heaters) were not microphonic. It all depends on what you can get.
Thanks Miles,
very low Rp is requested for my application
6BQ7A i don't know, I'll search datasheet.
Could be interesting if someone kind guys could be post his experience about 6H30 and 6C45P always talking about microphonicity, because expecially the 6C45P appears to my eyes very interesting !
Thanks a lot !
Cheers,
Paolo
very low Rp is requested for my application
6BQ7A i don't know, I'll search datasheet.
Could be interesting if someone kind guys could be post his experience about 6H30 and 6C45P always talking about microphonicity, because expecially the 6C45P appears to my eyes very interesting !
Thanks a lot !
Cheers,
Paolo
Hi Kevin,
A part the very little microphony ( remember I am fanatic ) 6N6P-I
after 20 hours of break in is sounding EXTREMLY good. And I am near incontentable
No contest with the previous 6922 cathode follower, it is a new world!
Sound is hot, refinied, harmonic dinamic and relaxing the same time.
To not talking about bass and midbass: very punchy!
In short I am very satisfied, Gordy have centered a very good point of work. I have to thanks you too because I have found your page in the web by google with your original schematic.
Thanks guys, wish you were here with me to listen my system,
not simply words but real music!
Cheers,
Paolo
A part the very little microphony ( remember I am fanatic
) 6N6P-Iafter 20 hours of break in is sounding EXTREMLY good. And I am near incontentable
No contest with the previous 6922 cathode follower, it is a new world!
Sound is hot, refinied, harmonic dinamic and relaxing the same time.
To not talking about bass and midbass: very punchy!
In short I am very satisfied, Gordy have centered a very good point of work. I have to thanks you too because I have found your page in the web by google with your original schematic.
Thanks guys, wish you were here with me to listen my system,
not simply words but real music!
Cheers,
Paolo
inertial said:Hi,
More accurately, I'm searching info about a near zero microphonic medium mu double triode. Low Rp is requested.
candidates are
E182 CC , ECC99, 5687, 6H30 or others
I have some E288CC philips SQ but they ring like bells
I can considerate also single triode.
I know EC8020 is the best but they are ultra expansive !
I appreciate any kind of suggestion
Thanks for help,
Paolo
Not great choice with such specifications among double triodes. All the valves you mention were not designed for audio (as main application) and so low microphony was not a design target.
If low microphony is very important and you consider single triodes, you might consider as well quality pentodes like C3g, C3m or E80L which also show excellent linearity when triode connected.
Cheers,
45
inertial said:Thanks 45, I am newbie so every suggestion is welcome
Cheers,
Paolo
You can find the curves (triode-connected) for the above valves
here:
http://frank.pocnet.net/sheets/062/e/E80L.pdf
http://frank.pocnet.net/sheets/062/c/C3g.pdf
http://frank.pocnet.net/sheets/128/c/C3m.pdf
Approximately all of them have Rp's in the range of 2.3k - 4K, depending on the operative conditions.
Cheers,
45
inertial said:thanks 45,
Unfortunately I need absolutely Rp = 1600 ohm or less
Paolo
What dictates the need for such a low rp? Perhaps a power follower or similar might be a way around this..
I think even the 5842/417A and D3A are hard pressed to meet this criteria even at insane plate currents.. It could well be that your choice of the 6N6 is the best for your application.
IMO There is almost no such thing as a completely non-microphonic type, I have encountered microphonic examples of almost everything I have ever used. Some will be way better than others, but to toss an otherwise good tube because of microphonics is unfortunate. Shock mounting and isolating them from sources of excitation go a long way toward making this a minor problem. (There will still be some that are not usable in a phono stage, but anywhere else this should usually not be a major issue.) I use 26 dhts in my system and I have been told flatly that they are hopeless in this regard, and they aren't - and every sample I have is quite microphonic. (I have only a few I consider unusable.)
Kevin, thanks for your comments
because I must drive this :
http://www.audiodesignguide.com/PowerFollower/index.html
As I said I am satisfied of my 6N6, but this do not mean that I do not must search to make even better!
I am curious about 6H30 e 6C45P.....................
I disagree about microphonics. I have 6922 sovtek ( not one but 8) and Mullard Ecc88 that have zero microphonicity. Rare but exist!
The bad of microphonicity is undervalutated IMHO, I have made experiments for years with vibrations so there is no possibility one can
make me change my idea
Cheers,
Paolo
because I must drive this :
http://www.audiodesignguide.com/PowerFollower/index.html
As I said I am satisfied of my 6N6, but this do not mean that I do not must search to make even better!
I am curious about 6H30 e 6C45P.....................
I disagree about microphonics. I have 6922 sovtek ( not one but 8) and Mullard Ecc88 that have zero microphonicity. Rare but exist!
The bad of microphonicity is undervalutated IMHO, I have made experiments for years with vibrations so there is no possibility one can
make me change my idea
Cheers,
Paolo
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